The 2017 Nobel Prize for Medicine & Physiology was awarded to three US researchers who discovered how the genetic and cellular mechanics of the body maintain stable, daily rest-and-activity cycles or circadian rhythms. A key point: All the systems of the body function in a specific rhythm that is synchronized with patterns of light and dark in our environment, controlled by a series of genes. One factor in this process, melatonin — the timekeeper for the body clock, synchronizing sleep-wake cycles — helps these genes carry out their job. So if melatonin is disrupted that can mean normal daily synchronization will be disrupted, and many systems throughout the body suffer. Researchers now recognize that one major consequence of a disruption in circadian rhythms is an increase in the incidence and severity of cancer.
What disrupts circadian rhythm? One example: Melatonin, as mentioned, is secreted naturally by the pineal gland in response to darkness. Anything that interferes with full darkness like blue light emitted from electronic devices — computer screens, smartphones, tablets and TVs — or even outdoor lights that shine into bedrooms, can interrupt melatonin production and thus upset the body clock. In fact, a recent study by Harvard University found that women who live in neighborhoods that have the highest levels of outdoor light at night have a 14% increase in breast cancer risk .
More concerning for current cancer patients are findings that correlate cancer survival with disruptions of circadian rhythm. In 4 different studies, researchers found that cancer patients with disrupted circadian rhythm have worse outcomes than those who have regular daily rhythms of sleep and activity. The percentage of patients who survived in a 2-year research was:
25% higher survival for lung cancer patients who had normal circadian rhythms
17% higher survival in breast cancer,
13% higher survival in colorectal cancer patients
11% higher survival in renal cancer patients.
So maintaining a good circadian rhythm could be a matter of life and death for cancer patients!
How do you tell if you have a disrupted circadian rhythm? One way is to assess your own sleep and activity patterns. Going to bed at different times each night and napping frequently during the day — for stretches of more than 30-35 minutes — can signal circadian disruption. So are restless nights, inability to fall back to sleep if awakening periodically, and unrelieved fatigue.
There are more scientifically accurate ways to measure circadian rhythm, however. Both melatonin and the stress hormone cortisol are secreted in regular but inverse circadian rhythms. That is, melatonin normally peaks during dark hours while cortisol is lowest during night time, and the reverse is true – melatonin hits lowest during daylight, but cortisol peaks approximately ½ hour before typical awakening time. Simple saliva tests can assess whether your own rhythms are normal or disrupted.
And what do you do if you learn that your circadian rhythm is disrupted? We’ll be offering tips on circadian normalization in this blog over the next few weeks, and also give you an advance look at some recent data on our patients indicating that instead of the badly disrupted circadian rhythms expected among metastatic cancer patients receiving chemotherapy, Block Center patients were scientifically shown to have entirely normal rhythms!